Voltage Level Detector (CB22135E)

We found this circuit in an English documentation from the 80's. Transistors are general-purpose types.

Dalayed Turn-On Gate (CB123)
This circuit can be used to add a delay to a logic signal as shown by the input and output...
Amplitude Modulated RF Amplifier (CB15007E)
This circuit was found in a Poptronics of the 90's. The FET is double-gate, and the frequency...
Water activated alarm (CB7993E)
This rain, flood or leak sensor was found in a 90s Popular Electronics. All the components used are...